Process of treating lumber



Patented Nov. 12,1929 1,735,001

' UNITED STATES PATENT'OFFICE DE VIBE DIEBKS, OF KANSAS CITY, MISSOURI PROCESS OF TREATING LUMBER No Drawing. Application filed June 28, 1927. Serial No. 802,168.

This invention relates to the manufacture original moisture content for an indefinite of lumber and is concerned more particularly period, or under severe conditions, changes with the production of dressed lumber which in moisture content onl at a relatively low is supplied to the trade for numerous purrate. To accomplish thls end I seal the lum- -'5 poses, such as flooring, interior trim, and the her immediately upon the completion of the 55 like, and is also used in the manufacture of drying operations, and for this purpose I various articles. I apply to the wood a sealing material or coat- Dressed lumber is now produced from ing which is substantially waterproof or im rough dimension stock which is dried, ordipervious to moisture. This material forms a.

'16 narily in kilns, to aselected moisture content, thin, clear, hard, surface film which closes 6 then surfaced by planers and sometimes given and seals the pores of the wood and also pera heading, or worked into mouldings and meates the wood toasubstantial extent. The other special forms. Upon the completion of sealing material in no way interferes with p p the dressin operations, the finished product the use of the lumber, but 1n addition to the is usually s ipped without delay for use, but primary function of sealing the pores of the 5 as it is exposed to varying atmospheric condiwood, it effects a substantial economy on betions during shipment and also 1n actual use, half of the ultimate consumer 1n that thethe moisture content frequently changes, sealing film serves as a riming coat and thus causing the lumber to shrink or swell as moisreduces the number 0 coats of finish orditure is lost or-taken up. Change in moisture narily required. 7

content also results 1n checking, cracking,' According to my invention, the sealing warping, etc., and any shipment consequently material is applied to the lumber immediately is liable to reach its destination with a perafter the latter has been dressed in approcentage of lumber falling below specification priate machines. For this purpose, the fin- Y and therefore rejected as unfit for use, or else. ished product is carried from the finishing 75 accepted as of an inferior quality. Such machines directly into abath of the sealing lumber not only represents an actual loss to material a conveyor be1n preferably emthe manufacturer in lower return, but also ployed for the purpose w 'ch receives the frequently results in claims for damage, so lumber from the dressing machines and car- '30 that changes in the lumber due to variation ries it into, through, and out of a tank in in the moisture content present a serious probwhich it is immersed in the sealin material lem. Similarly, the occurrence of defects in by a simple dipping operation. T e lumber the dressed lumber while in use, such as is then allowed to dry and the drying may shrinking, swelling, etc.,causes trouble to the be hastened by forced draft, if desired. After ultimate consumer and likewise injures the the surface is dry, the lumber may be shipped as reputation of the manufacturer, even though and each piece is coated with a thin, hard these defects arise from no fault in manufaclayer of the colorless sealin compound which ture. imparts a slight sheen or gloss to a planesur- These difficulties cannot be overcome by face, and also darkens t e wood to a very 49 improvements or alteration in the method of slight extent, so that the grain stands out dryin the rough stock since they do not more prominently." The lumber so treated is occur ecause of imperfet or insufiicient drynot subject to ordinary defects, such as variaing, but because of changes in the moisture tion in dimension, distortion, checking, cupcontent after the drying and dressing opera- I ping, etc., and thus is of superior quality and tions have been completed, and ma be the may be sold at ahigher marketpnce. result of loss of moisture, as well as o absorp- While it is generally satisfactory to ap ly tion. I the sealing material to the dressed lumber In order to avoid these defects in the immediately upon the completion of the dressdressed product, I have devised a niethod of ing operations, the best results may be ob- 50 producing dressed lumber which retains its tained by reducing to a minimum the length dominate.

, as a cobalt'dryer. Also,

of time that the lumber is exposed to the atmosphere after it leaves the kiln and before it is coated with the sealing material. At the end of the drying operation, the lumber taken from the kiln contains aselected amount of moisture, as, for exam le 7 or 8%, this content being determined by t e manner in which the drying operation is carried out in the kiln. This kiln-dried lumber should then be dressed with a minimum of delay and immediately after being finished and shaped to proper form, the dressed product should be sealed so that in the final product carrying a sealing coating on all its exterior surfaces there is present substantially the same amount of moisture present in the wood as it is taken from the kiln.

The solution which I prefer to use for the sealing treatment includes a number of ingredients which are-selected to produce a mixture of waterproofing quality and high penetrating power, this solution drying quickly so as to provide a hard, clear coating. In order to secure the necessary waterproofing qualities, China wood or tung oil is employed, this oil being first treated'to make-it capable of providing a waterproofing layer, according to any of the usual methods commonly employed for this purpose by varnish manufacturers. China wood oil thus treated is highly satisfactory forthe purpose, since it dries hard and clear.

To the treated China wood oil" is added a quantity of a suitable compound which will give the mixture the desired penetrating power, and for this purpose xylol may be used. Xylolis a constituent of coal tar naphtha well known among varnish manufacturers and it has the quality of penetrating the pores of wood, it dries rapidly, and it does not leave a greasy spot. Other comounds may be used to replace xylol, as, For example, so-called solvent naphtha or toluol, although xylol appears to be the most satisfactory. The desired material is one which penetrates rapidly, mingles freely with China wood oil, dries quickly, and does not stain. The proportions in which the waterproofing material and the penetratin material are emplo ed in' the mixture wil vary somewhat according to whether the qualities of waterproofingor penetrating are to pre- Likewise, the type of-penetrating material 'to be used may depend on the rate of drying desired. Commercial solvent naphtha evaporates somewhat more slowly than xylol, while toluol what more rapidly.

A solution for ordinary use may be made up of 50% treated China wood oil and 50% xylol. To the China wood oilmay be added a small amount of a suitable dryer, such if desired, a pigment may be added to the mixture, this pigment assisting to close the pores of the wood lumber receive a evaporates some and giving the surface a slight roughness so that finishing materials will adhere better. As a suitable pigment, numerous materials may be employed, such as a mixture of asbestine (magnesium silicate) 75%, china clay (aluminum silicate) 20%, and bentonite clay 5%. This pigment may be used in varying amounts with the mixture of China wood oil and the penetrating medium above described, as, for example, there may be mixed with the solution an amount of pigment equal to 2Q% of the total weight of the mixture. The pigment is prepared in the ordinary manner and is ground fine for use.

In carrying out the novel treatment, the rough stock dried to a selected moisture content, for example 8%, is sawed, planed, beaded, etc., in accordance with the standard practice to produce the desired product. The dressed lumber is then taken directly from the machines and dipped in the solution tanks, the lumber travelling through the tanks at a suitable rate of speed so that it is immersed for one or two minutes. During this immersion, the China wood oil is carried into the pores .of the wood by the penetrating medium to a substantial extent. Beyond the tanks the lumber is moved along slowly, so that the surface coating may dry to an extent sufficient to prevent tackiness and after the surface of the lumber has dried, it may be stacked or handled in the usual way, and the final drying may take place in the atmosphere and, if desired, during shipment.

Instead of applying the sealing material I by immersion, this operation may be performed by placing the lumber on a conveyor and running the pieces past spray nozzles which will discharge the material in sufiiclent amounts to insure that all parts of the coating. While it is generally preferable to apply the sealing material cold, in some instances it may be desirable to maintainthe liquid at a temperature above normal atmospheric. Similarly, for most purposes drying without artificial heat will be at a rate suificientl rapid to be satisfactory, but if desired, the drying may be accelerated either by heat or by fans. The details of the steps for carrying out the process will, to a large extent, depend on local conditions and on the type of wood which is undergoing treatment.

The sealing material which I have described as suitable for use In, my process forms a clear film and is thus satisfactory for general use, but in some instances, where it is known in advance that the wood is to be given a finish of a certain color, a suitable coloring material may be incorporated in the sealing solution which then acts as a vehicle.

Since the sealing material is used only in small quantities and it is applied by a simple factors;

a woo which absor dipping operation, as distin ished from im pregnation processes hereto ore used and involvin impre ation under reduced pres sure, t e cost 0 the finished roduct. is relatively low. The equipment necessary for carrying out the process is relatively inexpensive and due to the superior quality of the treated dressed lumber and its increased utility, in that it retains its dimensions and form and likewise carries a priming coat, this treated lumber may be sold at a price increase much more than sufiicient to cover the increase in production cost.

I have foundthat the treatment according to my invention is suitable for man difierent kinds of wood and is particularl satiswith gum, inc, and oak. um is and gives off moisture wlthegreat rapidity, so that its use is accompani by'many difliculties, due to chan e in moisture content. The application 0 the sealing material in accordance with my invention overcomes these difiiculties and makes it possible to use this wood for many purposes for which it has hitherto been considered entirely unsatisfactory. This is due to the fact that the coatin applied to the lumber in accordance wit the invention covers its entire exterior surface with a sub- I claim:

1. A method of roducing dressed lumber substantially free om defects due to change in moisture content, which comprises dressing rough dimension stock to proper size and shape, and immediately applying to the dressed product a seahng material substantially free from gums and forming a thin, hard'substantially waterf-proof envelope on all surfaces of the wood.

2. A metlfod of producing dressed lumber substantiallyfree from defects due to change in moisture content, which comprises drying rough dimension stock to a selected moisture content, dressin the stock to the desired pattern, and imm 'ately after the dressing operation is completed, ap lyin to the dressed product a seahn material an stantiall free rom gums and ormin a thin, hard su antiall water-proof enve ope on all surfaces of the umber. v I

3. A method of producing dressed lumber substantially free from defects due to change in moisture content, which comprises ln'lndrying rough dimension stock to a selected moisture content, dressing the dried stock to the desired pattern, and applying to all surfaces of the dressed product a thin, substantially waterproof film, substantially free from gums, the operations of dressing ,the lumber and applying the film thereto being carried on without substantial delay to avoid variation in the moisture content of the lumber from that present upon completion of the drying operation.

:1 4'. A method of producing lumber substantially free from defects due to change in moisture content, which comprises drying the lumber to a selected moisture content, and immediately applying to all surfaces of the lumber a sealing material substantiall free from gums which penetrates the woo to a substantial extent and also forms a thin, clear, substantially waterproof surface film having a slight sheen.

Y 5. .A method of roducing lumber, which comprises drying t e lumber to a selected moisture content, and applying to all surfaces of the dried lumber a mixture consisting of a water-proofing material and a volatile liquid hydrocarbon of high penetrating uality, this mixture being substantially free rom gums.

6. A method of producing lumber, which comprises drying the lumber to a selected moisture content and applying to all surfaces of the dried lumber a mixture consisting of a waterproofing material which dries hard and clear and a liquid. hydrocarbon which penetrates wood rapidly and dries quickly, this mixture being substantially free from gums.

7. A method of producing lumber, which comprises drying the lumber to a selected moisture content, and applyin to the dried lumber a mixture consisting 0 China wood oil treated to give it waterproofing qualities and a liquid hydrocarbon.

8. A method of producing lumber, which comprises drying the lumber to a selected moisture content, and applyin to the dried lumber a mixture consisting 0 China wood oil treated to. give it waterproofing qualities and 101.

9. method of producing lumber, which comprises drying the lumber to a selected moisture content, and applyin to the dried lumber a mixture consisting 0 China wood oil treated to give it waterproofing qualities and xylol, to which has been added a quantity of a pigment.

10. A method of producing lumber, which comprises drying the lumber to a selected moisture content, and applying to the dried lumber a mixture consisting of China wood oil treated to give it waterproofing qualities and xylol in approximately equal amounts.

11. A method of treating lumber which comprisesdrying the lumber to a moisture content approximating 8-per cent and coating the dried lumber with a mixture consisting of China wood oil treated to give it waterproofing qualities and a liquid hydrocarbon.

12. A method of treating lumber, which comprises drying the lumber to a selected 5 moisture content, immersing the dried lumber in a sealing compound consisting of a waterproofing material and a liquid of high penetrating qualities, the mixture being substntially free from gums. In testimony whereof I afiix 1n si nature. I DE VERE. 131E KS. 

